1. Mosquitoes may have developed resistance to the insecticide DDT through natural selection. Initially, there may have been a small percentage of mosquitoes with a genetic variation that allowed them to survive exposure to DDT. As the insecticide was repeatedly used and killed off susceptible mosquitoes, those with the genetic variation for resistance were more likely to survive and pass on their genes to the next generation. Over time, this led to an increase in the population of mosquitoes with DDT resistance.
2. Natural selection inhibited frog eggs from hatching any earlier than two days before expected hatching to ensure the embryos were developed enough to survive outside of the egg. Those eggs that hatched too early due to vibrations and resulted in underdeveloped embryos likely did not survive to reproduce, thus reducing the likelihood of this trait being passed down. This selective pressure favored eggs that hatched within the optimal time frame for survival.
3. The EPAS1 gene, which increases the ability of red blood cells to carry oxygen in low oxygen environments, is only common in Tibetan populations due to competitive advantage and natural selection. In the high elevations of Tibet, where oxygen levels are lower, individuals with the EPAS1 gene have a better chance of survival and reproduction compared to those without the gene. This gives them a selective advantage, leading to a higher frequency of the gene in the Tibetan population.
4. Natural selection leads to evolution as organisms with advantageous traits are more likely to survive, reproduce, and pass on those traits to future generations. This process can be seen through the four parts of natural selection: variation in traits among individuals, heritability of traits, differential survival and reproduction based on traits, and gradual change in the population over time. For example, in a population of giraffes, those with longer necks may have an advantage in reaching higher food sources, leading to increased survival and reproduction of individuals with this trait over time.
5. As a paleontologist searching for the “missing link” between two species, I studied the fossils of the mythical creatures known as griffins and unicorns. Evidence linking these species included similarities in skeletal structure, such as a unique formation of the ribcage and limbs. By analyzing the tooth morphology and diet of these creatures, I found correlations suggesting a shared ancestor and causations indicating adaptations for different ecological niches. This hypothesis was further supported by genetic analysis of ancient DNA extracted from fossil remains.
1.Mosquitoes can carry and transmit many diseases to humans. In the past, the insecticide DDT was heavily used to reduce mosquito populations in order to reduce instances of disease transmission. However, after some time, mosquito populations developed a resistance to DDT, which made the DDT less effective in reducing mosquito populations.
Based on what you’ve learned about natural selection, in 3–5 sentences, describe how mosquitoes may have come to develop this resistance.
2.Red-eyed tree frog eggs can hatch up to two days earlier than average when they detect vibrations. However, if they hatch more than two days earlier than expected due to vibrations, the embryos are typically not developed enough to survive outside of the egg. Explain how natural selection inhibited frog eggs from hatching any earlier than two days before expected hatching. Explain your answer in 1–2 sentences.
3.The Tibetans and Han Chinese share several genetic traits and DNA. However, the EPAS1 gene, which increases the ability of red blood cells to carry oxygen even in low oxygen environments, is only commonly found in the Tibetan population that live in higher elevations. Explain why this gene is only common in Tibetan populations from the perspective of competitive advantage and natural selection. Write your answer in three to five sentences.
4.In three to five sentences, construct an argument for the claim that natural selection leads to evolution. Provide evidence for this claim, and be sure to explain how an organism shows the four parts of the process of natural selection. You may use any organism with the exception of bacteria and antibiotic resistance.
5.Imagine you are a paleontologist trying to find the “missing link” between different species. In three to five sentences, create a fictional narrative about your discoveries, describing: 1) what two species, mythical or real, you are studying, 2) what evidence you have linking these species, and 3) what evidence you have to define different correlations and causations that support your hypothesis.
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